将来的任务附加到另一个循环 [英] Future task attached to a different loop

问题描述

我正在尝试在FastAPI中连接到mongodb.我屡屡遇到这种情况.

I am trying to connect to mongodb in FastAPI. I am repeatedly getting this exception.

文件-main.py

File - main.py

app = FastAPI(
    title=config.PROJECT_NAME, docs_url="/api/docs", openapi_url="/api"
)

@app.get("/api/testing")
async def testit():
    user_collection = readernetwork_db.get_collection("user_collection")
    all_users = await user_collection.find_one({"email": "sample_email"})
    print("all users --- ", all_users)
    return all_users

if __name__ == "__main__":
    uvicorn.run("main:app", host="0.0.0.0", reload=True, port=8888)

文件-session.py

File - session.py

import motor.motor_asyncio
from app.core import config


print("here we go again....")
client = motor.motor_asyncio.AsyncIOMotorClient(
    config.MONGOATLAS_DATABASE_URI)
readernetwork_db = client.get_database("readernetwork")

例外-:

all_users = await user_collection.find_one({"email": "sample_email"})

RuntimeError: Task <Task pending name='Task-4' coro=<RequestResponseCycle.run_asgi() running at /usr/local/lib/python3.8/site-packages/uvicorn/protocols/http/h11_impl.py:389> cb=[set.discard()]> got Future <Future pending cb=[_chain_future.<locals>._call_check_cancel() at /usr/local/lib/python3.8/asyncio/futures.py:360]> attached to a different loop

我不知道我在哪里弄错了.我应该为马达指定一个事件循环吗?

I don't know where I am getting this wrong. Should I specify a event loop to motor?

推荐答案

您可以在全局范围内使用 mongodb motor 客户端，但是创建和关闭它应该在异步函数中完成.在应用程序的 startup 和 shutdown 处理程序中执行此操作的最佳方法.像这样:

You can have mongodb motor client in the global scope, but creating and closing it should be done inside an async function. The most preferable way of doing that in startup and shutdown handler of the application. Like so:

# mongodb.py
from motor.motor_asyncio import AsyncIOMotorClient


db_client: AsyncIOMotorClient = None


async def get_db_client() -> AsyncIOMotorClient:
    """Return database client instance."""
    return db_client


async def connect_db():
    """Create database connection."""
    db_client = AsyncIOMotorClient(DB_URL)

async def close_mongo_connection():
    """Close database connection."""
    db_client.close()

# main.py
app = FastAPI(title=PROJECT_NAME)
...
app.add_event_handler("startup", connect_db)
app.add_event_handler("shutdown", close_db)

这篇关于将来的任务附加到另一个循环的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！